Segment routing, also known as source based routing, has been used in electronic routers in communication networks. Segment routing is at least in part enabled by the at least one node in an optical network knowing the topology of the network including how each node is connected to another. A packet traversing a segment routed network typically includes a header and a payload. The header of a segment routed packet will typically include complete routing information. The routing information typically includes is a list of nodes and/or links that the packet is routed over to traverse the network. When a node in the segment routed network receives a packet, it can determine where to forward the packet by inspecting the routing information stored in the header. Before forwarding the packet, the node will typically remove an address from the source routing list. In another implementation, in place of a list of node addresses, the source routing list includes a list of the ports that each node should forward the packet to. In such an embodiment, when a node receives a packet it routes the packet to the port identified in the header and removes the port from the list. Each node in the network performs the same process.
Currently, segment routing has been implemented at a network layer. To obtain the segment routing information, the packet header must be read in the electrical domain. In segment routed networks making use of optical links, the optical signal must be converted into the electrical domain so that the routing information can be read. Any required modifications to the header are then performed, and the packet is forwarded. The forwarding process often involves a reconversion into the optical domain for transmission on an optical link. This optical-electrical-optical (O-E-O) conversion process is time and resource intensive.
Routing of signals in an optical network is intended to be fast, and accordingly there is limited processing time per node. Continuing to improve the performance of optical networks may help to satisfy increasing demand for both bandwidth and speed in telecommunication networks.